Polymer materials having self-healing properties have been actively investigated in recent years. In a hydrogel formed by crosslinking via an ordinary covalent bond, once the bond is cut, binding back is impossible. Therefore, self-healing has been difficult.
As self-healing materials that restore themselves via a non-covalent bond whose binding reversible, materials having hydrogen bonds, bonds utilizing ionic interaction, aromatic π-π interaction, metal complex formation, and coordination bonding, and dynamic covalent bonds utilizing formation of radicals that easily bind and dissociate are known (Patent Literature (PTL) 1). However, none of the bonds are sufficient in terms of bonding strength. Further, self-healing materials formed via the above bonds rebind at a site different from the cleavage site, and also have problems in terms of shape-memory properties.